Question

Q11- Consider equation: Pb⁺² (aq) + 2OH⁻ (aq) → Pb(OH)₂ (s). precipitate of lead (II) hydroxide will be of
A) Green color
B) Blue color
C) Brown color
D) White color

Q12- Consider equation: Cu⁺² (aq) + 2OH⁻(aq) → Cu(OH)₂ (s). precipitate of Copper Hydroxide (Cu(OH)₂) will be of
A) Green color
B) Blue color
C) Brown color
D) White color

Answer 1

Answer:

q no. 11 brown colour

qno.12 white colour

Answer 2

The questions are answered as follows:

Q11- Precipitate of lead (II) hydroxide will be of D) White colour.

Q12- Precipitate of Copper Hydroxide (Cu(OH)₂) will be of B) Blue colour.

1. Lead hydroxide

$Pb^{+2} (aq) +2OH^{-} (aq) \rightarrow Pb(OH)_{2} (s)$

• The above reaction is an example of the redox reaction as lead undergoes oxidation, and at the same time, hydroxide ion undergoes reduction.
• The product obtained, lead hydroxide is also known as plumbous hydroxide or basic lead carbonate.
• In lead (II) hydroxide, (II) indicates that lead is present in +2 oxidation state. Its colour is white.

2. Copper hydroxide

$Cu^{+2}(aq) + 2OH^{-}(aq) \rightarrow Cu(OH)_{2} (s)$

• The above reaction is similar to the previous one.
• Here, copper hydroxide is obtained as precipitate, which is blue in colur.